LOUISVILLE, Colo. — NASA will postpone the remainder of an ongoing series of spacewalks at the International Space Station to upgrade batteries for its power system after a related component malfunctioned and needs to be replaced.
NASA announced Oct. 15 that the third in a series of battery replacement spacewalks that had been scheduled for Oct. 16, featuring NASA astronauts Jessica Meir and Andrew Morgan, had been postponed after a device called a battery charge/discharge unit, or BCDU, failed on the station over the weekend. The device is used to charge the batteries as part of the station’s power supply.
Instead, NASA will carry out a spacewalk either Oct. 17 or 18 to replace the failed BCDU unit with a spare on the station. Meir and Christina Koch will carry out that spacewalk. The two had been scheduled to perform an Oct. 21 spacewalk to replace batteries, the first all-female NASA spacewalk.
In an interview here during a media event for Sierra Nevada Corporation’s Dream Chaser cargo vehicle, Kirk Shireman, NASA ISS program manager, said the BCDU units were turned off before an Oct. 11 spacewalk to replace batteries, but otherwise not touched. Three such units were switched off for the spacewalk, and two turned back on normally afterwards. The third, though, failed to turn on.
“We believe the battery is fine,” he said, but without a working BCDU, that power channel now produces only two-thirds of its rated power. That led to the decision to carry out a spacewalk to replace the charging unit.
Shireman said that NASA doesn’t plan to immediately resume spacewalks to complete the battery replacement work, a task the agency expected to take five spacewalks. “We’re going to stand down, probably for a few weeks,” he said, to determine if the BCDU failure was caused by something done during the battery replacement process. “We don’t believe that’s the case, but we want to go take some time and look at all the data.”
The timing of the remaining battery replacement spacewalks, including how many more will be needed, will also depend the ability to keep a mobile work platform by the site with equipment needed for the battery replacement. “There are some implications of leaving it out there” that are still being studied, he said. NASA had planned to complete the spacewalks Oct. 25.
The battery replacement spacewalks were just the start of an intense period of activity outside the station. Later this fall Morgan and Luca Parmitano will carry out an additional set of five spacewalks to replace coolant pumps on the Alpha Magnetic Spectrometer (AMS) instrument on the station. That effort is complicated by the fact that the AMS was not designed for in-space repairs, requiring special training for the astronauts.
Besides the battery replacement and AMS repair spacewalks, Russian cosmonauts Alexander Skvortsov and Oleg Skripochka are scheduled to carry out a spacewalk Oct. 31 on the station’s Russian segment.